Its the third one for the answer
C=1500+4x where x is cds, C is cost
R=10x where R is revenue
then, P=R-C
P=10x-1500-4x
P=6x-1500
set P=0
1500=6x
x=250
check, C=1500+4*250, R=10*250
C=250, R=250
They need to sell 250 cds before they make profit
The answer is the same as the question. 1.75
6(x²-4x+4-4)+1=0, 6(x-2)²-24+1=0, 6(x-2)²=23, x-2=±√(23/6), x=2±√(23/6)=2±1.95789, so x=3.95789 or 0.04211 approx. These are the zeroes.
I believe it is use sugar and and release carbon. We breath in oxygen so you know it can’t be anything where we release oxygen. And I don’t know how we could release nitrogen so I would go with the second one
